[Follicular neoplasm of the thyroid: usefulness of extemporaneous histologic study of frozen sections]. / Neoplasia follicolare della tiroide: utilità dell'esame istologico estemporaneo al congelatore.

PURPOSE: The role of frozen section (FS) in determining thyroidectomy extent in patients with follicular neoplasms is debated. The Authors consider FS usefulness through experience retrospective review. MATERIAL AND METHODS: From January 1980 to June 1999, 1252 Fine Needle Aspirations (FNA) were performed in patients with thyroid nodules. Out of these, 155 (12.4%) resulted follicular neoplasms. All these patients were operated on: 54 had total thyroidectomy because of both lobes disease and 101 had emithyroidectomy with FS. FS results were compared to definitive histological examination. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of frozen section have been estimated. RESULTS: Out of 155 follicular neoplasms, 15 resulted malignant at definitive histological examination: 6 were diagnosed by FS. All 6 patients had a total thyroidectomy during the same operation. Of the rimanenti 9, 6 had a second operation for radicalization within 2-3 days. FS sensitivity was 42.9%, specificity 100%, accuracy 92.0%, PPV 100% and NPV 8.5%. DISCUSSION: Some Authors consider FS useful because it allows to radicalize the operation immediately, in case of positivity for malignancy. Even if only few patients, the possibility to solve the problem in a one-step procedure is a great advantage. Other Authors consider FS useless because to diagnose a poor number malignant neoplasms, a lot of intra-operative examination have to be done. Costs are higher than benefits. CONCLUSIONS: The Authors believe that both attitudes are correct and the decision of using or not FS cannot be standardized.